Negative electrode active material for non-aqueous electrolyte secondary battery and manufacturing method thereof

Abstract

The invention provides a negative electrode active material for a nonaqueous electrolyte secondary battery and a manufacturing method thereof. To provide a coated particle effective as a negative electrode active material and a production method thereof, and a lithium ion having a negative electrode using the same, for providing a non-aqueous electrolyte secondary battery capable of obtaining a high battery capacity while maintaining silicon oxide, high initial charge and discharge efficiency, and excellent cycle characteristics Secondary batteries and electrochemical capacitors. Method for producing negative electrode active material consisting of coated particles with carbon film Heat treatment of particles selected from silicon oxide particles, composite particles having a structure in which silicon nanoparticles are dispersed in silicon oxide, and mixed particles thereof without introducing organic gas Finally, the obtained heat-treated particles are subjected to chemical vapor deposition (CVD) treatment in an organic gas; it is characterized in that the temperature of the above-mentioned heat treatment (the highest temperature in the heat treatment) is set as T1, and the temperature in the chemical vapor deposition process (chemical vapor phase The highest temperature in the deposition process) is set to T2, and T1>T2.

Description

Negative electrode active material for non-aqueous electrolyte secondary battery and manufacturing method thereof technical field The present invention relates to a method for producing coated particles having a carbon coating having high initial charge and discharge efficiency and good cycle characteristics when used as a negative electrode active material for a lithium ion secondary battery, a negative electrode active material for a lithium ion secondary battery, and This negative electrode active material is used for a negative electrode lithium ion secondary battery and an electrochemical capacitor. Background technique In recent years, along with the remarkable development of portable electronic devices, communication devices, and the like, there has been a strong demand for nonaqueous electrolyte secondary batteries with high energy density from the viewpoints of economy, size reduction, and weight reduction of devices. Hitherto, as measures for increasing the capac...

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Problems solved by technology

However, since silicon oxide has a large irreversible capacity and an initial efficiency of about 70%, it is very low. Therefore, in the case of actually making a battery, it is necessary to make the battery capacity of the positive electrode excessive, and it cannot be expected that only the active material equivalent to 5- Increase of battery capacity for capacity increase of 6 times

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